Magento: Admin Controller Override

Consideration: MyNameSpace = PG and MyModule = Deletecc
Note:1:We are taking example of OrderController.php of \app\code\core\Mage\Adminhtml\controllers    \Sales.
         2:This Module is applicable for Magento-1.4.0.x

Create Your own module and files as follows:
Magento/app/code/local/PG/Deletecc/etc/config.xml
Magento/app/code/local/PG/Deletecc/controllers/Sales/OrderController.php
Magento/app/etc/modules/PG_Deletecc.xml

Now Edit config.xml :
Go to Magento/app/code/local/PG/Deletecc/etc/config.xml and paste the following xml code into it


Edit /controllers/Sales/OrderController.php:
Paste the following php code into Magento/app/code/local/PG/Deletecc/controllers/Sales/OrderController.php (the only change we’re doing to the indexAction() is adding an error_log() message):



Edit Magento/app/etc/modules/PG_Deletecc.xml
Add the below code to  enable the your module.



That's It..